Propulsion system for a buoyant aerial vehicle

ABSTRACT

A buoyant aerial vehicle includes: a balloon configured to store a gas; a payload coupled to the balloon; and a propulsion unit coupled to the payload by a tether. The propulsion unit includes: a fuselage having a substantially longitudinal shape, a first end, and a second end; a primary airfoil coupled to the fuselage; a secondary airfoil coupled to the fuselage at one of the first end or the second end; and a thrust generating device disposed at one of the first end or the second end and configured to move the propulsion unit relative to the payload along a propulsion flight path. The movement of the propulsion unit imparts movement of the buoyant aerial vehicle along a vehicle flight path.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/850,824, filed on Dec. 21, 2017, the disclosure of which isincorporated herein by reference.

BACKGROUND

Some buoyant aerial vehicles are capable of controlled flight. Suchaerial vehicles rely on some form of thrusters to control lateralmovement. However, such systems have substantial power requirements,whether in the form of batteries or fuel, to power the motors orengines. As such, simpler, more efficient propulsion systems for buoyantaerial vehicles could be beneficial in improving their maneuverability.

SUMMARY

According to one aspect of the present disclosure, a buoyant aerialvehicle includes: a balloon configured to store a gas; a payload coupledto the balloon; and a propulsion unit coupled to the payload by atether. The propulsion unit includes: a fuselage having a substantiallylongitudinal shape, a first end, and a second end; a primary airfoilcoupled to the fuselage; a secondary airfoil coupled to the fuselage atone of the first end or the second end; and a thrust generating devicedisposed at one of the first end or the second end and configured tomove the propulsion unit relative to the payload along a propulsionflight path. The movement of the propulsion unit imparts movement of thebuoyant aerial vehicle along a vehicle flight path.

In embodiments of the above aspect of the present disclosure, the tetheris coupled to the primary airfoil. Tether is also coupled to a winchconfigured to adjust a length of the tether by which the propulsion unitextends from the payload.

In further embodiments of the above aspect of the present disclosure, atleast one of the primary airfoil or the secondary airfoil includes atleast one aileron. At least one of the primary airfoil or the secondaryairfoil also includes at least one solar panel.

In other embodiments of the above aspect of the present disclosure, thepropulsion unit includes a controller configured to actuate at least onethe primary airfoil, the secondary airfoil, or the thrust generatingdevice to move the propulsion unit relative to the payload along thepropulsion flight path. The propulsion flight path may have a cyclical,reversible pattern.

In embodiments of the above aspect of the present disclosure, the thrustgenerating device includes an electrical motor and a propeller rotatableby the electrical motor.

In further embodiments of the above aspect of the present disclosure, avehicle controller is included and configured to receive a movementcommand including at least one of a destination, direction, or speed formoving the buoyant aerial vehicle along the vehicle flight path. Thepropulsion unit further includes a propulsion controller configured tocommunicate with the vehicle controller. At least one of the vehiclecontroller or the propulsion controller is configured to determine thepropulsion flight path that propels the buoyant aerial vehicle along thevehicle flight path.

The propulsion controller is further configured to control the primaryairfoil, the secondary airfoil, and the thrust generating device.

In other embodiments of the above aspect of the present disclosure, thepropulsion unit further includes a sensor configured to measure at leastone flight property of the propulsion unit. The sensor is configured totransmit a measurement value corresponding to the at least one flightproperty to at least one of the vehicle controller or the propulsioncontroller.

According to another aspect of the present disclosure, a method forcontrolling an aerial vehicle includes: transmitting a movement commandto a buoyant aerial vehicle having a propulsion unit attached thereto bya tether; determining, based on the movement command, a propulsionflight path for the propulsion unit to achieve a vehicle flight pathcorresponding to the movement command; and controlling at least one of aprimary airfoil, a secondary airfoil, or a thrust generating device ofthe propulsion unit to move the propulsion unit along the propulsionflight path.

In embodiments of the above aspect of the present disclosure, the methodincludes: adjusting a length of a tether coupling the propulsion unit tothe buoyant aerial vehicle.

In further embodiments of the above aspect of the present disclosure,the method further includes: measuring at least one flight property ofthe propulsion unit; and communicating a measurement of the at least oneflight property to at least one of a vehicle controller of the buoyantaerial vehicle or a propulsion controller of the propulsion unit.

According to further aspect of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions is disclosed,which, when executed by a processor, cause a computing device to:transmit a movement command to a buoyant aerial vehicle having apropulsion unit attached thereto by a tether; determine, based on themovement command, a propulsion flight path for the propulsion unit toachieve a vehicle flight path corresponding to the movement command; andcontrol at least one of a primary airfoil, a secondary airfoil, or athrust generating device of the propulsion unit to move the propulsionunit along the propulsion flight path.

In embodiments of the above aspect of the present disclosure, thecomputing device is further caused to: control a winch to adjust alength of a tether coupling the propulsion unit to the buoyant aerialvehicle.

In further embodiments of the above aspect of the present disclosure,the computing device is further caused to: determine at least one flightproperty of the propulsion unit; and communicate a measurement of the atleast one flight property to at least one of a vehicle controller of thebuoyant aerial vehicle or a propulsion controller of the propulsionunit.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and features of the present systems and methods forcontrolling an aerial vehicle are described herein below with referencesto the drawings, wherein:

FIG. 1 is a schematic diagram of an illustrative aerial vehicle system,in accordance with an embodiment of the present disclosure;

FIG. 2 is a schematic diagram showing additional aspects of the aerialvehicle system of FIG. 1, in accordance with an embodiment of thepresent disclosure;

FIG. 3 is a schematic block diagram of an illustrative embodiment of acomputing device that may be employed in various embodiments of thepresent system, for instance, as part of the system or components ofFIG. 1 or 2, in accordance with an embodiment of the present disclosure;

FIG. 4A is a schematic diagram of the aerial vehicle system of FIG. 1illustrating a propulsion flight path of a propulsion unit in accordancewith an embodiment of the present disclosure;

FIG. 4B is a schematic diagram of the aerial vehicle system of FIG. 1illustrating a propulsion flight path of a propulsion unit in accordancewith another embodiment of the present disclosure;

FIG. 5 is a perspective view of a propulsion unit of the aerial vehiclesystem of FIG. 1 in accordance with an embodiment of the presentdisclosure; and

FIG. 6 is a perspective view of a propulsion unit of the aerial vehiclesystem of FIG. 1 in accordance with another embodiment of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure is directed to systems and methods for propellinga buoyant aerial vehicle. In embodiments, the buoyant aerial vehicleincludes a wing-based propulsion unit that is attached to a payload ofthe aerial vehicle, such that the propulsion unit is suspended from thepayload, e.g., by a tether. The propulsion unit is powered by a thrustgenerating device, such as an electrically powered propeller. Thepropulsion unit is configured to perform a cyclically reversing flightpath, thereby generating movement along the swing line of the propulsionunit, which in turn generates lift. The lift vector of the propulsionunit is controlled by adjusting the direction and/or speed of thepropulsion unit, which in turn allows for controlling steering andpropulsion of the buoyant aerial vehicle.

Although the present disclosure makes particular reference tosuperpressure balloons, which are designed to float at an altitude inthe atmosphere where the density of the balloon system is equal to thedensity of the atmosphere, this is being used for illustrative purposesonly. The propulsion system according to the present disclosure may beused with any vehicles that maintain altitude at least in part by usingbuoyancy, such as other types of balloons, airships, and the like.

With reference to FIG. 1, an illustrative aerial vehicle system 100includes an aerial vehicle 102, one or more computing devices 104, andone or more data sources 106. The aerial vehicle 102 and the computingdevices 104 are communicatively coupled to one another by way of awireless communication link 108, and the computing devices 104 and thedata sources 106 are communicatively coupled to one another by way ofwired and/or wireless communication link 110. In some aspects, theaerial vehicle 102 is configured to be launched into and moved about theatmosphere, and the computing devices 104 cooperate as a ground-baseddistributed array to perform their functions described herein. The datasources 106 may include airborne data sources, such as airborne weatherballoons, additional airborne aerial vehicles 102, and/or the like,and/or ground-based data sources, such as publicly available and/orproprietary databases, examples of which are the Global Forecast System(GFS) operated by the National Oceanic and Atmospheric Administration(NOAA), as well as databases maintained by the European Center forMedium-range Weather Forecasts (ECMWF). Although the present disclosureis provided in the context of an embodiment where the system 100includes multiple computing devices 104 and multiple data sources 106,in other embodiments the system 100 may include a single computingdevice 104 and a single data source 106. Further, although FIG. 1 showsa single aerial vehicle 102, in various embodiments the system 100includes a fleet of multiple aerial vehicles 102 that are positioned atdifferent locations throughout the atmosphere and that are configured tocommunicate with the computing devices 104, the data sources 106, and/orone another by way of the communication links 108 and/or 110.

In various embodiments, the aerial vehicle 102 may be configured toperform a variety of functions or provide a variety of services, suchas, for instance, telecommunication services (e.g., Long Term Evolution(LTE) service), hurricane monitoring services, ship tracking services,services relating to imaging, astronomy, radar, ecology, conservation,and/or other types of functions or services. Computing devices 104control the position (also referred to as location) and/or movement ofthe aerial vehicles 102 throughout the atmosphere or beyond, tofacilitate effective and efficient performance of their functions orprovision of their services, as the case may be. As described in furtherdetail herein, the computing devices 104 are configured to obtain avariety of types of data from a variety of sources and, based on theobtained data, communicate messages to the aerial vehicle 102 to controlits position and/or movement during flight.

With continued reference to FIG. 1, the aerial vehicle 102 includes alift gas balloon 112, one or more ballonets 116, and a payload orgondola 114, which is suspended beneath the lift gas balloon 112 and/orthe ballonets 116 while the aerial vehicle 102 is in flight. Theballonets 116 may be used to control the buoyancy, and thereby thealtitude, of the aerial vehicle 102 during flight. In some aspects, theballonets 116 include air and the lift gas balloon 112 includes alifting gas that is lighter than air. As shown in FIG. 1, the ballonets116 may be positioned inside the lift gas balloon 112 and/or outside thelift gas balloon 112. An vehicle controller 126 controls a pump and avalve (neither of which are shown in FIG. 1) to pump air into theballonets 116 (from air outside the aerial vehicle 102) to increase themass of the aerial vehicle 102 and lower its altitude, or to release airfrom the ballonets 116 (into the atmosphere outside the aerial vehicle102) to decrease the mass of the aerial vehicle 102 and increase itsaltitude. The combination of the vehicle controller 126, the lift gasballoon 112, the ballonets 116, and the valves and pumps (not shown inFIG. 1) is referred to as an air-gas altitude control system (ACS).

The aerial vehicle 102 also includes one or more solar panels 134affixed thereto. As shown in FIG. 1, the solar panels 134 may be affixedto an upper portion of the lift gas balloon 112 that absorbs sunlight,when available, and generate electrical energy from the absorbedsunlight. Alternatively, or in addition, the solar panels 134 may beaffixed to the gondola 114 or elsewhere to aerial vehicle 102 (not shownin FIG. 1). The solar panels 134 provide, by way of power paths such aspower path 136, the generated electrical energy to the variouscomponents of the aerial vehicle 102, such as components housed withinthe gondola 114, for utilization during flight.

The gondola 114 includes a variety of components, some of which may ormay not be included, depending upon the application and/or needs of theaerial vehicle 102. Although not expressly shown in FIG. 1, the variouscomponents of the aerial vehicle 102 in general, and/or of the gondola114 in particular, may be coupled to one another for communication ofpower, data, and/or other signals. The exemplary gondola 114 shown inFIG. 1 includes one or more sensors 128, an energy storage module 124, apower plant 122, a vehicle controller 126, a transceiver 132, and otheron-board equipment 130. The transceiver 132 is configured to wirelesslycommunicate data between the aerial vehicle 102 and the computingdevices 104 and/or data sources 106 by way of the wireless communicationlink 108 and/or the communication link 110, respectively.

In some embodiments, the sensors 128 include a global positioning system(GPS) sensor that senses and outputs location data, such as latitude,longitude, and/or altitude data corresponding to a latitude, longitude,and/or altitude of the aerial vehicle 102 in the Earth's atmosphere. Thesensors 128 are configured to provide the location data to the computingdevices 104 by way of the wireless transceiver 132 and the wirelesscommunication link 108 for use in controlling the aerial vehicle 102, asdescribed in further detail below.

The energy storage module 124 includes one or more batteries that storeelectrical energy provided by the solar panels 134 for use by thevarious components of the aerial vehicle 102. The power plant 122obtains electrical energy stored by the energy storage module 124 andconverts and/or conditions the electrical energy to a form suitable foruse by the various components of the aerial vehicle 102.

The vehicle controller 126 is configured to control the ballonets 116 toadjust the buoyancy of the aerial vehicle 102 to assist in controllingits position and/or movement during flight. As described in furtherdetail below, in various embodiments the vehicle controller 126 isconfigured to control the ballonets 116 based at least in part upon analtitude command that is generated by, and received from, the computingdevices 104 by way of the wireless communication link 108 and thetransceiver 132. In some examples, the vehicle controller 126 isconfigured to implement the altitude command by causing the actuation ofthe ACS based on the altitude command.

The on-board equipment 130 may include a variety of types of equipment,depending upon the application or needs, as outlined above. For example,the on-board equipment 130 may include LTE transmitters and/orreceivers, weather sensors, imaging equipment, and/or any other suitabletype of equipment.

In addition to the aforementioned components, the gondola 114 is alsocoupled a propulsion unit 140. The propulsion unit 140 is attached tothe gondola 114 by a winch 120, which allows for controlling thedistance between the propulsion unit 140 and the aerial vehicle 102. Thewinch 120 may be coupled to the gondola 114 as shown in FIGS. 4A and 4B.In embodiments, the winch 120 may be coupled to the propulsion unit 140as shown in FIG. 6.

The propulsion unit 140 includes one or more sensors 142, a propulsioncontroller 144, energy storage 146, flight controls 148, and a thruster150. The energy storage 146, which may be any suitable electricalbattery, is coupled to one or more solar panels 152 attached thepropulsion unit 140.

Having provided an overview of the aerial vehicle system 100 in thecontext of FIG. 1, reference is now made to FIG. 2, which shows certainoperations of the aerial vehicle system 100, in accordance with anembodiment of the present disclosure. In particular, FIG. 2 illustratesan exemplary embodiment of corresponding components are allocated amongthe aerial vehicle 102, the computing devices 104, and/or the datasources 106, to control a position and/or movement of the aerial vehicle102 and how they function. The arrangement of components depicted inFIG. 2 is provided by way of example and not limitation. Otherarrangements of components and allocations of functionality arecontemplated, for instance, with the aerial vehicle 102 includingcomponents that implement functionality shown in FIG. 2 as beingimplemented by the computing devices 104, or vice versa. However, in theexample shown in FIG. 2, a majority of components and functionality areallocated to the computing devices 104 instead of to the aerial vehicle102, which decreases the amount of energy required to operate thecomponents of the aerial vehicle 102 and thus enables the components ofthe aerial vehicle 102 to utilize a greater portion of the availableenergy than would be possible if more components and functionality wereallocated to the aerial vehicle 102. This increases the capabilities ofthe aerial vehicle 102 for implementing functionality and/or providingservices for a given amount of available energy.

In addition to certain components that were introduced above inconnection with FIG. 1, FIG. 2 shows a wind mixer module 202, anavigation module 204, and a maneuver automation module 206 that areincluded within the computing devices 104. Once the aerial vehicle 102is in flight in the atmosphere, the sensors 128 are configured toperiodically transmit to the wind mixer module 202, by way of thetransceiver 132 and the wireless communication link 108, location data,such as time stamped GPS positions and altitudes of the aerial vehicle102 at corresponding times. The wind mixer module 202 utilizes thelocation data obtained from the sensors 128 and wind pattern dataobtained from other data sources 106 (such as National Oceanic andAtmospheric Administration (NOAA) data sources, European Centre forMedium-Range Weather Forecasts (ECMWF) data sources, and/or the like) toinfer or estimate the winds in which the aerial vehicle 102 is flying oris expected to be flying. In particular, wind points are stored in thewind mixer module 202, which constructs a kernel function, such as aGaussian Process kernel function that assists the navigation module 204in determining how to navigate the aerial vehicle 102 based on theinferred or estimated winds, according to one or more predeterminednavigation algorithms. Depending upon the navigation algorithm beingimplemented, the navigation module 204 generates a maneuver plan (e.g.,navigation data), which is a set of locations (e.g., altitudes, latitudecoordinates, and/or longitude coordinates) that the aerial vehicle 102should attempt to attain at corresponding times. Additionally, thenavigation module 204 receives weather data, including ambienttemperature conditions and/or predictions, from the data sources 106and/or from the sensors 128 via the transceiver 132. Based on thetemperature predictions, the navigation module 204 may determineadjustments to the maneuver plan including commands to the propulsionunit 140 to implement the maneuver plan, as further described below. Thenavigation module 204 then registers the maneuver plan with the maneuverautomation module 206.

The maneuver automation module 206 sequentially transfers each item oflocation data (e.g., altitude, latitude, and/or longitude) to thevehicle controller 126 for implementation according to the correspondingtimes indicated in the maneuver plan. In particular, the maneuverautomation module 206 transmits to the transceiver 132, by way of thewireless communication link 108, a movement command, which includes analtitude command (for example, which may be specified as a barometricpressure, which may be equivalent to pressure altitude, and whichindicates a desired altitude for the aerial vehicle 102 to maintainwithin some tolerance band) and/or a speed and direction command. Thevehicle controller 126 is configured to execute a loop whereby thevehicle controller 126 periodically receives the altitude command and/ora speed and direction command from the computing devices 104 andexecutes those commands to control the altitude as well as direction andspeed of the aerial vehicle 102.

With respect to the speed and direction command, the vehicle controller126 transmits the command to the propulsion controller 144 of thepropulsion unit 140. The propulsion controller 144 then determines howto best implement the speed and direction command to move the aerialvehicle 102. In particular, the propulsion unit 140 signals the flightcontrols 148 and the thruster 150 to move the propulsion unit 140 in apropulsion flight path 160, which would result in propulsion of theaerial vehicle 102 along a vehicle flight path 162 (FIGS. 4A and 4B). Inaddition, the vehicle controller 126 and/or the propulsion controller144 are coupled to the winch 120 and are configured to control the winch120 to adjust the distance that the propulsion unit 140 extends from theaerial vehicle 102.

FIG. 3 is a schematic block diagram of a computing device 300 that maybe employed in accordance with various embodiments described herein.Although not explicitly shown in FIG. 1 or FIG. 2, in some embodiments,the computing device 300, or one or more of the components thereof, mayfurther represent one or more components (e.g., the computing device104, components of the gondola 114, the data sources 106, the propulsionunit 140 and/or the like) of the system 100. The computing device 300may, in various embodiments, include one or more memories 302,processors 304, display devices 306, network interfaces 308, inputdevices 310, and/or output modules 312. The memory 302 includesnon-transitory computer-readable storage media for storing data and/orsoftware that is executable by the processor 304 and which controls theoperation of the computing device 300. In embodiments, the memory 302may include one or more solid-state storage devices such as flash memorychips. Alternatively, or in addition to the one or more solid-statestorage devices, the memory 302 may include one or more mass storagedevices connected to the processor 304 through a mass storage controller(not shown in FIG. 3) and a communications bus (not shown in FIG. 3).Although the description of computer readable media included hereinrefers to a solid-state storage, it should be appreciated by thoseskilled in the art that computer-readable storage media may be anyavailable media that can be accessed by the processor 304. That is,computer readable storage media includes non-transitory, volatile andnon-volatile, removable and non-removable media implemented in anymethod or technology for storage of information such ascomputer-readable instructions, data structures, program modules orother data. Examples of computer-readable storage media include RAM,ROM, EPROM, EEPROM, flash memory or other solid state memory technology,CD-ROM, DVD, Blu-Ray or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium which may be used to store the desired informationand which can be accessed by computing device 300.

In some embodiments, the memory 302 stores data 314 and/or anapplication 316. In some aspects the application 316 includes a userinterface component 318 that, when executed by the processor 304, causesthe display device 306 to present a user interface, for example agraphical user interface (GUI) (not shown in FIG. 3). The networkinterface 308, in some embodiments, is configured to couple thecomputing device 300 and/or individual components thereof to a network,such as a wired network, a wireless network, a local area network (LAN),a wide area network (WAN), a wireless mobile network, a Bluetoothnetwork, the Internet, and/or another type of network. The input device310 may be any device by means of which a user may interact with thecomputing device 300. Examples of the input device 310 include withoutlimitation a mouse, a keyboard, a touch screen, a voice interface,and/or the like. The output module 312 may, in various embodiments,include any connectivity port or bus, such as, for example, a parallelport, a serial port, a universal serial bus (USB), or any other similarconnectivity port known to those skilled in the art.

With reference to FIGS. 4A and 4B, the aerial vehicle 102 is shown withthe propulsion unit 140 attached thereto by a tether 156 that is woundabout the winch 120. The tether 156 may be any rope or cable havingsuitable tensile properties for supporting the propulsion unit 140 thatallows for the propulsion unit 140 to fly in any direction relative tothe aerial vehicle 102. The propulsion unit 140 is configured to movealong the propulsion flight path 160 (FIG. 4A) or a propulsion path 161(FIG. 4B) relative to the aerial vehicle 102, since the propulsion unit140 is tethered thereto. The propulsion flight path 160 may be anycyclical path and may have any suitable shape, such as circular, oval,obround, and combinations thereof. In embodiments, the propulsion flightpath 160 may also be any cyclically reversible, e.g., ondulating, flightpath that is substantially disposed along a swing plane 163.

As the propulsion unit 140 moves along the propulsion flight path 160(FIG. 4A) or the propulsion path 161 (FIG. 4B), the propulsion unit 140generates lift. The lift vector of the propulsion unit 140 is controlledby adjusting the direction of propulsion unit 140, which in turn allowsfor controlling steering and propulsion of the aerial vehicle along thevehicle flight path 162 at a set speed and direction. With respect tothe embodiment of FIG. 4B, the lift vector of the propulsion unit 140 issubstantially transverse to the swing plane 163 and is used to point,and thus, steer the aerial vehicle 102. Thus, the flight path 162 isalso substantially transverse with respect to the swing plane 163.

With reference to FIG. 5, the propulsion unit 140 includes a fuselage170, a primary airfoil 172, e.g., a pair of wings, a secondary airfoil174, e.g., a tail, and the thruster 150. In embodiments, the secondaryairfoil 174 may include a stabilizer. The primary airfoil 172 may bedisposed at about the midpoint of the fuselage 170 and is attached tothe tether 156. The secondary airfoil 174 is disposed at a second, e.g.,rear, end 182 of the fuselage 170, which is opposite of a first, e.g.,front, end 180.

The thruster 150 may be a micro propeller powered by an electrical motor176 and a propeller 178, which is coupled to and rotatable by theelectrical motor 176. The electrical motor 176 and the propeller 178 aredisposed at the first end 180 of the fuselage 170 and provide propulsionto the propulsion unit. In this configuration, the thruster 150 operatesin a tractor configuration, such that the propulsion unit 140 is pulledthrough the air. The electrical motor 176 may be powered by the energystorage 146, which stores electrical energy generated by the solarpanels 152. The solar panels 152 may be on any portion of propulsionunit 140, e.g., on the primary airfoil 172 and/or the secondary airfoil174. In exemplary embodiments, the thruster 150 may be disposed at thesecond end 182, and would be configured in a pusher configuration, suchthat the propulsion unit 140 is pushed through the air.

Each of the primary airfoil 172 and the secondary airfoil 174 mayinclude one or more ailerons 184 that may be used to control directionof the propulsion unit 140. As described above in FIG. 2, the propulsioncontroller 144 is configured to operate the flight controls 148, whichinclude the thruster 150 and the ailerons 184, to control the flight ofthe propulsion unit 140. This includes operating the flight controls 148to guide to propulsion unit 140 along the propulsion flight path 160 toachieve a desired speed and/or direction of the propulsion unit 140, togenerate lift and by extension, propel the aerial vehicle 102 along thevehicle flight path 162.

The sensors 142 of the propulsion unit 140 measure various flight dataparameters, such as air pressure, wind velocity, etc. The sensors 142transmit this data to the vehicle controller 126 and/or the propulsioncontroller 144, which then make adjustments to the propulsion flightpath 160 and/or the vehicle flight path 162.

The propulsion unit 140 may move in any cyclical flight path having anysuitable shape, e.g., obround, oval, circular, and combinations thereofetc., as shown in FIG. 4A. The pitch, roll, and yaw of the propulsionunit 140 may be varied during the propulsion flight path 160 byadjusting any or all of the ailerons 184 disposed on the primary andsecondary airfoils 172 and 174 as well as the thruster 150. Inembodiments, the propulsion flight path 160 may be adjusted bycontrolling the direction as well as velocity of the propulsion unit140. In other words, the propulsion controller 144 would instruct theflight controls 148 of the propulsion unit 140 to execute half a loop ateach end to generate a cyclical pattern.

Alternatively, the propulsion unit 140 may move along a cyclicallyreversible undulating propulsion flight path 161. The propulsion flightpath 161 may be adjusted by controlling the thruster 150 such that thepropulsion unit 140 undulates along the propulsion flight path 161. Itis envisioned that ailerons 184 may also be adjusted to ensure that thepropulsion unit 140 stays within the swing plane 163. The thruster 150may be operated in a cyclical manner such that the thruster 150 switchesbetween tractor and pusher configurations. In order to propel thepropulsion unit 140 along the propulsion flight path 161, the thruster150 is operated at a variable speed to ensure that the velocity andacceleration vectors of the propulsion unit 140 correspond to theundulating trajectory of the propulsion flight path 161. Thus, as thepropulsion unit 140 is approaching either end of the propulsion flightpath 161, the velocity of the propulsion unit 140 approaches zero. Atthese points, the thruster 150 reverses the direction of the thrust(e.g., switches between the tractor and pusher configurations) to propelthe propulsion unit 140 in a reverse direction.

With reference to FIG. 6, another embodiment of a propulsion unit 240 isshown. The propulsion units 140 and 240 may be used interchangeably withrespect to the flight paths 160 and 161 of FIGS. 4A and 4B, or any otherdesired flight paths. Since the propulsion unit 240 is suspended fromthe aerial vehicle 102, aerodynamic demands on the propulsion unit 240are different from a conventional aircraft that needs to maintain flightwithout the aid of another aerial vehicle, e.g., aerial vehicle 102.Accordingly, the propulsion unit 240 may include any number or airfoilshaving any suitable shape or size designed to achieve directionalcontrol and drag reduction of the propulsion unit 140 to achieve flightcontrol of the aerial vehicle 102 rather than of the propulsion unit140.

The propulsion unit 240 is substantially similar to the propulsion unit140 of FIG. 5, and only the differences are described below. Inparticular, the propulsion unit 240 may include a primary airfoil 272having a single a wing extending from the fuselage 170. In addition, thepropulsion unit 240 may include the winch 120 that is coupled to theprimary airfoil 272. In exemplary embodiments, the winch 120 may also becoupled to the primary airfoil 172 of the propulsion unit 140.

Various operational parameters of the propulsion unit 140 or 240, suchas tether extension, direction and speed of the propulsion flight path160 may be controlled remotely in order to move the aerial vehicle 102to a desired destination. Commands to the propulsion unit 140 may besent from the computing devices 104 through the vehicle controller 102or directly to the propulsion controller 144. Commands may include GPScoordinates to instruct the aerial vehicle 102 to move to a desiredlocation. The vehicle controller 126 would then communicate with thepropulsion controller 144 to achieve the desired positioning of theaerial vehicle 102 by moving the propulsion unit 140 or 240 along thepropulsion flight path 160 to generate movement, e.g., desired speed anddirection, along the vehicle flight path 162. Thus, the vehiclecontroller 126, upon receiving movement commands from the computingdevices 104, is configured to generate propulsion commands for thepropulsion unit 140 or 240 to move the aerial vehicle 102 along thevehicle flight path 162. In embodiments, the vehicle controller 126and/or the propulsion controller 144 may control the winch 120 to adjustthe distance of the tether 156 to make additional adjustments to thepropulsion flight path 160 since the length of the tether 156 directlyaffects the length of the propulsion flight path 160.

In embodiments, in addition to being used to generate desired movement,the propulsion unit 140 or 240 may be also used as a sail to guide theaerial vehicle 102 using wind currents. In further embodiments, thepropulsion unit 140 or 240 may be used as an anchor to counteract anymovement of the aerial vehicle 102 due to atmospheric conditions, e.g.,currents. In these embodiments, the propulsion unit 140 or 240 islowered into lower reaches of the atmosphere and the flight controls 148are used to maintain the position and orientation of the propulsion unit140 or 240 relative to the wind current depending on the desired effectsof the winds (e.g., to minimize or maximize the surface area of theprimary airfoil 272 or the primary and secondary airfoils 172 and 174exposed to the wind).

As can be appreciated in view of the present disclosure, the systems andmethods described herein provide advancements in aerial vehiclepropulsion. The disclosed system minimizes the need for multiple thrustgenerating devices by using a single thruster to move the aerial vehiclein any desired direction. The present disclosure also provides for a lowcost and low weight propulsion system that can be integrated within theexisting framework of any buoyant aerial vehicle system by beingsuspended from the payload. In addition, the disclosed propulsion unithas minimal power requirements for generating propulsion, whichleverages atmospheric conditions, e.g., wind, and/or momentum to movethe balloon. Furthermore, the configuration of the propulsion unitprovides for additional surface area for mounting solar panels.

The embodiments disclosed herein are examples of the present systems andmethods and may be embodied in various forms. For instance, althoughcertain embodiments herein are described as separate embodiments, eachof the embodiments herein may be combined with one or more of the otherembodiments herein. Specific structural and functional details disclosedherein are not to be interpreted as limiting, but as a basis for theclaims and as a representative basis for teaching one skilled in the artto variously employ the present information systems in virtually anyappropriately detailed structure. Like reference numerals may refer tosimilar or identical elements throughout the description of the figures.

The phrases “in an embodiment,” “in embodiments,” “in some embodiments,”or “in other embodiments” may each refer to one or more of the same ordifferent embodiments in accordance with the present disclosure. Aphrase in the form “A or B” means “(A), (B), or (A and B).” A phrase inthe form “at least one of A, B, or C” means “(A); (B); (C); (A and B);(A and C); (B and C); or (A, B, and C).”

The systems and/or methods described herein may utilize one or morecontrollers to receive various data and transform the received data togenerate an output. The controller may include any type of computingdevice, computational circuit, or any type of processor or processingcircuit capable of executing a series of instructions that are stored ina memory. The controller may include multiple processors and/ormulticore central processing units (CPUs) and may include any type ofprocessor, such as a microprocessor, digital signal processor,microcontroller, programmable logic device (PLD), field programmablegate array (FPGA), or the like. The controller may also include a memoryto store data and/or instructions that, when executed by the one or moreprocessors, causes the one or more processors to perform one or moremethods and/or algorithms. In exemplary embodiments that employ acombination of multiple controllers and/or multiple memories, eachfunction of the systems and/or methods described herein can be allocatedto and executed by any combination of the controllers and memories.

Any of the herein described methods, programs, algorithms or codes maybe converted to, or expressed in, a programming language or computerprogram. The terms “programming language” and “computer program,” asused herein, each include any language used to specify instructions to acomputer, and include (but is not limited to) the following languagesand their derivatives: Assembler, Basic, Batch files, BCPL, C, C+, C++,Delphi, Fortran, Java, JavaScript, machine code, operating systemcommand languages, Pascal, Perl, PL1, scripting languages, Visual Basic,metalanguages which themselves specify programs, and all first, second,third, fourth, fifth, or further generation computer languages. Alsoincluded are database and other data schemas, and any othermeta-languages. No distinction is made between languages which areinterpreted, compiled, or use both compiled and interpreted approaches.No distinction is made between compiled and source versions of aprogram. Thus, reference to a program, where the programming languagecould exist in more than one state (such as source, compiled, object, orlinked) is a reference to any and all such states. Reference to aprogram may encompass the actual instructions and/or the intent of thoseinstructions.

Any of the herein described methods, programs, algorithms or codes maybe contained on one or more non-transitory computer-readable ormachine-readable media or memory. The term “memory” may include amechanism that provides (in an example, stores and/or transmits)information in a form readable by a machine such a processor, computer,or a digital processing device. For example, a memory may include a readonly memory (ROM), random access memory (RAM), magnetic disk storagemedia, optical storage media, flash memory devices, or any othervolatile or non-volatile memory storage device. Code or instructionscontained thereon can be represented by carrier wave signals, infraredsignals, digital signals, and by other like signals.

The foregoing description is only illustrative of the present systemsand methods. Various alternatives and modifications can be devised bythose skilled in the art without departing from the disclosure.Accordingly, the present disclosure is intended to embrace all suchalternatives, modifications and variances. The embodiments describedwith reference to the attached drawing figures are presented only todemonstrate certain examples of the disclosure. Other elements, steps,methods, and techniques that are insubstantially different from thosedescribed above and/or in the appended claims are also intended to bewithin the scope of the disclosure.

What is claimed is:
 1. A method for controlling a buoyant aerial vehicleincluding a payload and a balloon configured to store a gas, the methodcomprising: managing, by a first controller of the buoyant aerialvehicle, airflow into and out of a ballonet operatively associated withthe balloon, in order to adjust an altitude of the buoyant aerialvehicle; and moving, by a thrust generating device of a propulsion unitof the buoyant aerial vehicle, the propulsion unit along a propulsionflight path, such that moving the propulsion unit imparts movement ofthe buoyant aerial vehicle along a vehicle flight path; wherein movingthe propulsion unit along the propulsion flight path includescontrolling, by a second controller of the buoyant aerial vehicle thatis part of the propulsion unit, at least one of a direction and avelocity of the propulsion unit for the propulsion flight path in orderto move the buoyant aerial vehicle along the vehicle flight path.
 2. Themethod of claim 1, further comprising the second controller actuatingthe thrust generating device to move the propulsion unit relative to theballoon along the propulsion flight path.
 3. The method of claim 1,further comprising the second controller receiving a movement commandincluding at least one of a destination, selected direction, or speedfor moving the buoyant aerial vehicle along the vehicle flight path. 4.The method of claim 3, wherein the movement command is received from thefirst controller.
 5. The method of claim 3, wherein the movement commandis received from a computing device remote from the buoyant aerialvehicle.
 6. The method of claim 1, further comprising determining thepropulsion flight path.
 7. The method of claim 6, wherein the propulsionflight path is determined by either the first controller or the secondcontroller.
 8. The method of claim 1, further comprising measuring, by asensor of the propulsion unit, at least one flight property of thepropulsion unit.
 9. The method of claim 8, further comprisingtransmitting, by the sensor, a measurement value corresponding to the atleast one flight property to at least one of the first controller or thesecond controller.
 10. The method of claim 1, further comprising thepayload of the buoyant aerial vehicle providing telecommunicationservice to one or more remote devices.
 11. The method of claim 1,wherein controlling at least one of the direction and the velocity ofthe propulsion unit for the propulsion flight path includes controllinga motor of the thrust generating device to cause a propeller to rotatein a selected direction of thrust.
 12. A method of controlling alighter-than-air vehicle during operation in the atmosphere where adensity of the lighter-than-air vehicle is equal to a density of theatmosphere, the method comprising: obtaining, by a vehicle controller ofthe lighter-than-air vehicle, a movement command, the movement commandincluding at least one of a destination, direction, or speed for movingthe lighter-than-air vehicle along a vehicle flight path; actuating, bythe vehicle controller, an altitude control system to adjust an altitudeof the lighter-than-air vehicle; and actuating, by a propulsioncontroller of a propulsion unit of the lighter-than-air vehicle, atleast one propeller to affect at least one of a direction and a velocityof the propulsion unit along a propulsion flight path in order to move apayload of the lighter-than-air vehicle along the vehicle flight path.13. The method of claim 12, further comprising receiving the obtainedmovement command from a computing device remote from thelighter-than-air vehicle.
 14. The method of claim 12, wherein actuatingthe at least one propeller includes altering a direction of thrust topropel the propulsion unit in a selected direction.
 15. The method ofclaim 12, further comprising determining the propulsion flight path. 16.The method of claim 15, wherein the propulsion flight path is determinedby either the vehicle controller or the propulsion controller.
 17. Themethod of claim 12, further comprising varying a pitch of the propulsionunit by adjusting a component of the lighter-than-air vehicle.
 18. Themethod of claim 12, further comprising: measuring, by one or moresensors of the propulsion unit, at least one of air pressure or windvelocity; and adjusting, by the propulsion controller, the propulsionflight path based on the measured air pressure or measured windvelocity.
 19. The method of claim 12, wherein a lift vector of thepropulsion unit is controlled by adjusting at least one the direction orvelocity of the propulsion unit.
 20. The method of claim 12, wherein thelighter-than-air aerial vehicle is an airship.